Visibility studies in archaeology: a review and case study

This paper describes the history and current state of archaeological visibility studies. The first part is a survey of both GIS (geographic information systems) and non-GIS studies of visibility by archaeologists, which demonstrates how advances in GIS visibility studies have tended to recapitulate, albeit over a compressed timescale, theoretically driven developments in non-GIS studies. The second part presents an example of the kind of methodological development required for the use of GIS to contribute to the agenda set by certain strands of a more humanistic archaeology. An algorithm developed to retrieve various summaries of the inclination at which points on the horizon are visible from a specified viewpoint was applied to nineteen recumbent stone circles in the Grampian region of Scotland. The results suggest that these summaries provide a useful tool for 'unpacking' what archaeologists mean when they claim that the topographic setting of certain stone circles creates an 'impression of circularity'

Visibility graphs and landscape visibility analysis

Visibility analysis based on viewsheds is one of the most frequently used GIS analysis tools. In this paper we present an approach to visibility analysis based on the visibility graph. A visibility graph records the pattern of mutual visibility relations in a landscape, and provides a convenient way of storing and further analysing the results of multiple viewshed analyses for a particular landscape region. We describe how a visibility graph may be calculated for a landscape. We then give examples, which include the interactive exploration ofa landscape, and the calculation of new measures of a landscape?s visual properties based on graph metrics ? in particular, neighbourhood clustering coefficient and path length analysis. These analyses suggest that measures derived from the visibility graph may be of particular relevance to the growing interest in quantifying the perceptual characteristics of landscapes

The visual preferences for forest regeneration and field afforestation : four case studies in Finland

The overall aim of this dissertation was to study the public's preferences for forest regeneration fellings and field afforestations, as well as to find out the relations of these preferences to landscape management instructions, to ecological healthiness, and to the contemporary theories for predicting landscape preferences. This dissertation includes four case studies in Finland, each based on the visualization of management options and surveys. Guidelines for improving the visual quality of forest regeneration and field afforestation are given based on the case studies. The results show that forest regeneration can be connected to positive images and memories when the regeneration area is small and some time has passed since the felling. Preferences may not depend only on the management alternative itself but also on the viewing distance, viewing point, and the scene in which the management options are implemented. The current Finnish forest landscape management guidelines as well as the ecological healthiness of the studied options are to a large extent compatible with the public's preferences. However, there are some discrepancies. For example, the landscape management instructions as well as ecological hypotheses suggest that the retention trees need to be left in groups, whereas people usually prefer individually located retention trees to those trees in groups. Information and psycho-evolutionary theories provide some possible explanations for people's preferences for forest regeneration and field afforestation, but the results cannot be consistently explained by these theories. The preferences of the different stakeholder groups were very similar. However, the preference ratings of the groups that make their living from forest - forest owners and forest professionals - slightly differed from those of the others. These results provide support for the assumptions that preferences are largely consistent at least within one nation, but that knowledge and a reference group may also influence preferences.Väitöskirjassa tutkittiin ihmisten maisemapreferenssejä (maisemallisia arvostuksia) metsänuudistamishakkuiden ja pellonmetsitysten suhteen sekä analysoitiin näiden preferenssien yhteyksiä maisemanhoito-ohjeisiin, vaihtoehtojen ekologiseen terveyteen ja preferenssejä ennustaviin teorioihin. Väitöskirja sisältää neljä tapaustutkimusta, jotka perustuvat hoitovaihtoehtojen visualisointiin ja kyselytutkimuksiin. Tapaustutkimusten pohjalta annetaan ohjeita siitä, kuinka uudistushakkuiden ja pellonmetsitysten visuaalista laatua voidaan parantaa. Väitöskirjan tulokset osoittavat, että uudistamishakkuut voivat herättää myös myönteisiä mielikuvia ja muistoja, jos uudistusala on pieni ja hakkuun välittömät jäljet ovat jo peittyneet. Preferensseihin vaikuttaa hoitovaihtoehdon lisäksi mm. katseluetäisyys, katselupiste ja ympäristö, jossa vaihtoehto on toteutettu. Eri viiteryhmien (metsäammattilaiset, pääkaupunkiseudun asukkaat, ympäristönsuojelijat, tutkimusalueiden matkailijat, paikalliset asukkaat sekä metsänomistajat) maisemapreferenssit olivat hyvin samankaltaisia. Kuitenkin ne ryhmät, jotka saavat ainakin osan elannostaan metsästä - metsänomistajat ja metsäammattilaiset - pitivät metsänhakkuita esittävistä kuvista hieman enemmän kuin muut ryhmät. Nämä tulokset tukevat oletusta, että maisemapreferenssit ovat laajalti yhteneväisiä ainakin yhden kansan tai kulttuurin keskuudessa, vaikka myös viiteryhmä saattaa vaikuttaa preferensseihin jonkin verran. Nykyiset metsämaisemanhoito-ohjeet ovat pitkälti samankaltaisia tässä väitöskirjassa havaittujen maisemapreferenssien kanssa. Myöskään tutkittujen vaihtoehtoisten hoitotapojen ekologisen paremmuuden ja niihin kohdistuvien maisemallisten arvostusten välillä ei ollut suurta ristiriitaa. Kuitenkin joitakin eroavaisuuksia oli; esimerkiksi sekä maisemanhoito-ohjeiden että ekologisten hypoteesien mukaan säästöpuut tulisi jättää ryhmiin, kun taas ihmiset pitivät eniten yksittäin jätetyistä puista. Informaatiomalli ja psyko-evolutionaarinen teoria tarjoavat mahdollisia selityksiä uudistushakkuisiin ja pellonmetsitykseen kohdistuville preferensseille, vaikkakaan tutkimuksen tuloksia ei voida täysin selittää näillä teorioilla

Analysing the visual dynamics of spatial morphology

Recently there has been a revival of interest in visibility analysis of architectural configurations. The new analyses rely heavily on computing power and statistical analysis, two factors which, according to the postpositivist school of geography, should immediately cause us to be wary. Thedanger, they would suggest, is in the application of a reductionist formal mathematical description in order to `explain' multilayered sociospatial phenomena. The author presents an attempt to rationalise how we can use visibility analysis to explore architecture in this multilayered context by considering the dynamics that lead to the visual experience. In particular, it is recommended that we assess the visualprocess of inhabitation, rather than assess the visibility in vacuo. In order to investigate the possibilities and limitations of the methodology, an urban environment is analysed by means of an agent-based model of visual actors within the configuration. The results obtained from the model are compared with actual pedestrian movement and other analytic measurements of the area: the agents correlate well both with human movement patterns and with configurational relationship as analysed by space-syntax methods. The application of both methods in combination improves on the correlation with observed movement of either, which in turn implies that an understanding of both the process of inhabitation and the principles of configuration may play a crucial role in determining the social usage of space

Risk-driven behaviour in the African leopard:how is leopard behaviour mediated by lion presence?

Agricultural expansion is restricting many carnivore species to smaller tracts of land, potentially forcing increased levels of overlap between competitors by constraining spatial partitioning. Understanding encounters between competitors is important because competition can influence species densities, distributions, and reproductive success. Despite this, little is known of the mechanisms that mediate coexistence between the African leopard (Panthera pardus) and its competitors. This project used GPS radiocollar data and playback experiments to understand risk-driven changes in the leopard’s behaviour and movement during actual and perceived encounters with lions (Panthera leo). Targeted playbacks of lion roars were used to elucidate immediate and short-lived behavioural responses in leopards when lions were perceived to be within the immediate area. To investigate the post-encounter spatial dynamics of leopard movements, the project used datasets from high-resolution GPS radiocollars deployed on leopards and lions with overlapping territories in the Okavango Delta, Botswana. Leopards were found to adapt behaviours and movements when lions were perceived to be nearby. Specifically, roar playbacks elicited longer periods of vigilance than controls, and movement directions were influenced by speaker locations. Further, leopard movements were quicker and more directional after encountering lions. However, adjustments in behaviour and movement were short-lived. The results provide insights into mechanisms used by the leopard to coexist with its competitors and are a useful case study of the methods that could be used to investigate encounter dynamics within other systems

Valuing the landscape benefits of rural policies actions in Veneto (Italy)

<p class="p1">This study addresses, with reference to the landscape, a precise request of the EU to quantify the benefits of public expenditure in agriculture. It analyses the implications on rural landscape of some measures of the Common Agricultural Policy at a regional level, taking the Rural Development Programme (RDP) 2007-2013 of the Veneto Region, in north-eastern Italy, as case study. A choice experiment (CE) is applied to value four measures of the RDP that directly affect the landscape characteristics.<br />The CE results point out that the landscape benefits of the measures in the Veneto RDP are higher than the subsidies paid to farmers for the provision of services that improve landscape quality. The CE results suggest the opportunity to rethink the distribution of the subsidies.</p

Empirical Evaluation of Route-Based Landscape Experiences

This thesis explores a method of visual analysis that aims to create a more in-depth understanding of how individuals see and visually perceive their environment. Here we explore a geospatial tool, called Visual Magnitude, to assess road-based experiences. We aimed to provide evidence of a relationship between the tool and scenic rating preferences from a survey. The content of this thesis is split between two articles. The first article, contained in Chapter 2, focuses on optimizing the selection of viewpoints along route-based envrionments. In this study we ask the question is there an optimal sampling rate of viewpoints along a route that can increase efficency in running a visual magnitude analysis and still represent accurately represent the envrionment. We found that for visually sensitive areas, a 30-meter sampling distance produced optimal results. For other landscapes a 50-meter sampling distance poduced resonable results in both sampling points and retained raster area. The second article, contained in Chapter 3, is an applied visual magnitude study where we use the optimal sampling distance of 30-meters to extract visual magnitude values for 15 different envrionments. These values are then compared to scenic rating values that we collected though a survey where participants saw videos of the same 15 envrionments and rated their scenic quailty. By doing this we were able to provide emperical evidence that the visual magnitude tool can be a way to predict best visual experiences within Utah. With the results from these studies we can make suggestions to professionals on how they can better use this GIS tool. These suggestions include sampling distances for multiple envrionments and the potential for this tool to be used as a poxy when attempting to interpret how landscapes observers feel about them. This additional infromation will help planners in understanding and making decisions more informed planning decisions along roadways and surrounding areas that have the highest potential impact on observers. By using this tool planners can assess where those areas are and the amount of impact that positive or negitive planning decisions will have on observers

An Empirical Assessment of the Arcpro Visual Magnitude Viewshed Plugin

Numerous viewshed analyses have been developed over the past few decades, but the uptake of these within industry has largely remained stagnant. This project involves ground-truthing one of the more recent viewshed analysis variants (Chamberlain and Meitner 2012, 2015) to assess reliability and application. This viewshed analysis was developed as a plug-in for the ESRI ArcGIS Pro software, making it readily accessible by anyone with an ArcGIS license. The validation of this software was recently conducted using an empirical approach to measure the accuracy of the analysis in the GIS versus real- world. Results demonstrate extremely high validity in controlled conditions, this degree of validity decreased substantially in highly variable terrain. This variability likely stems from measurement controls that are difficult to produce in real-world contexts. In this paper, the analysis, procedures and lessons learned are provided, as well as a call for additional empirical testing of viewshed analyses more broadly

Towards a landscape potential: A method based on a systematic characterization of the surrounding urban fabric through the visual dynamics of pedestrians

International audienceThe pedestrian mobility is a way to understand how a person might experience the void in between the buildings (this void defines a space portion as a shape) and therefore the urban fabric itself. The present paper aims to characterize landscape potentialities through pedestrian perception. Our proposal consists in building a set of sort of sensory Digital Elevation Models in which the third dimension is computed based on a measure of the surrounding open spaces using isovists. More precisely, we present three different DEMs: a first one corresponds to the isovist area in each point, the second one corresponds to its drift value (a frequently used indicator in isovist fields) and the third one corresponds to its kurtosis value. At last we combine all these DEMs with different pedestrian pathways so as to obtain corresponding sensory fingerprints

A call for viewshed ecology : Advancing our understanding of the ecology of information through viewshed analysis

JA was supported by funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 661211, and JMJT by NERC grant NE/J008001/1.Peer reviewedPostprin